let data = (“John Doe”, 42)

printf “%A” data
// Output: (“John Doe”,42)

public class Tuple<T1>
up to:
public class Tuple<T1, T2, T3, T4, T5, T6, T7, TRest>

using System;
using System.Linq;
using System.Collections.Generic;

namespace TupleTest
{
   class TupleCS4
   {
  #region Methods (4)

  // Public Methods (4)

       public static Tuple<string, string> GetFNameLName(string name)
       {
           if (string.IsNullOrWhiteSpace(name))
               throw new NullReferenceException("name is empty.");

           var nameParts = name.Split(',');

           if (nameParts.Length != 2)
               throw new FormatException("name must contain ','");

           return Tuple.Create(nameParts[0], nameParts[1]);
       }

       public static void PrintSelectedTuple()
       {
           var list = new List<Tuple<string, int>>
                          {
                              new Tuple<string, int>("A", 1),
                              new Tuple<string, int>("B", 2),
                              new Tuple<string, int>("C", 3)
                          };

           var item = list.Where(x => x.Item2 == 2).SingleOrDefault();
           if (item != null)
               Console.WriteLine("Selected Item1: {0}, Item2: {1}",
                   item.Item1, item.Item2);
       }

       public static void PrintTuples()
       {
           var tuple1 = new Tuple<int>(12);
           Console.WriteLine("tuple1 contains: item1:{0}", tuple1.Item1);

           var tuple2 = Tuple.Create("Item1", 12);
           Console.WriteLine("tuple2 contains: item1:{0}, item2:{1}",
               tuple2.Item1, tuple2.Item2);

           var tuple3 = Tuple.Create(new DateTime(2010, 5, 6), "Item2", 20);
           Console.WriteLine("tuple3 contains: item1:{0}, item2:{1}, item3:{2}",
               tuple3.Item1, tuple3.Item2, tuple3.Item3);
       }

       public static void Tuple8()
       {
           var tup =
               new Tuple<int, int, int, int, int, int, int, Tuple<int, int>>
                   (1, 2, 3, 4, 5, 6, 7, new Tuple<int, int>(8, 9));

           Console.WriteLine("tup.Rest Item1: {0}, Item2: {1}",
                   tup.Rest.Item1,tup.Rest.Item2);
       }

  #endregion Methods
   }
}

using System;

namespace TupleTest
{
   class Program
   {
       static void Main()
       {
           var data = TupleCS4.GetFNameLName("Vahid, Nasiri");
           Console.WriteLine("Data Item1:{0} & Item2:{1}",
                   data.Item1, data.Item2);

           TupleCS4.PrintTuples();

           TupleCS4.PrintSelectedTuple();

           TupleCS4.Tuple8();

           Console.WriteLine("Press a key...");
           Console.ReadKey();
       }
   }
}

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; } = null!;
    public CustomerType Type { get; set; }
}

public enum CustomerType
{
    Individual,
    Institution,
}

void ManyQueriesManyCalls()
{
    using var scope = serviceProvider.CreateScope();
    var context = scope.ServiceProvider.GetRequiredService<CustomerContext>();

    var baseQuery = context.Customers.Select(customer => new
                                                         {
                                                             customer.Name,
                                                             customer.Type,
                                                             customer.Id,
                                                         });
    var total = baseQuery.Count();
    var types = baseQuery.GroupBy(x => x.Type)
                         .Select(x => x.Key).ToList();
    var pageSize = 10;
    var pageIndex = 0;
    var results = baseQuery
                  .OrderBy(x => x.Id)
                  .Skip(pageSize * pageIndex)
                  .Take(pageSize)
                  .ToList();
    Console.WriteLine($"Total:{total}, First Type: {types.First()}, First Item: {results.First().Name}");
}

void ManyQueriesOnCall()
{
    using var scope = serviceProvider.CreateScope();
    var context = scope.ServiceProvider.GetRequiredService<CustomerContext>();
    var baseQuery = context.Customers.Select(customer => new
                                                         {
                                                             customer.Name,
                                                             customer.Type,
                                                             customer.Id,
                                                         });
    var pageSize = 10;
    var pageIndex = 0;
    var allTogether = baseQuery
                      .GroupBy(x => 1)
                      .Select(bq => new
                                    {
                                        Total = baseQuery.Count(),
                                        Types = baseQuery.GroupBy(x => x.Type)
                                                         .Select(x => x.Key)
                                                         .ToList(),
                                        Results = baseQuery
                                                  .OrderBy(x => x.Id)
                                                  .Skip(pageSize * pageIndex)
                                                  .Take(pageSize)
                                                  .ToList(),
                                    })
                      .FirstOrDefault();

    Console.WriteLine($"Total:{allTogether.Total}, First Type: {allTogether.Types.First()}, First Item: {allTogether.Results.First().Name}");
}

      SELECT [t0].[Key], [t1].[Type], [t2].[Name], [t2].[Type], [t2].[Id]
      FROM (
          SELECT TOP(1) [t].[Key]
          FROM (
              SELECT 1 AS [Key]
              FROM [Customers] AS [c]
          ) AS [t]
          GROUP BY [t].[Key]
      ) AS [t0]
      OUTER APPLY (
          SELECT [c0].[Type]
          FROM [Customers] AS [c0]
          GROUP BY [c0].[Type]
      ) AS [t1]
      OUTER APPLY (
          SELECT [c1].[Name], [c1].[Type], [c1].[Id]
          FROM [Customers] AS [c1]
          ORDER BY [c1].[Id]
          OFFSET @__p_1 ROWS FETCH NEXT @__pageSize_2 ROWS ONLY
      ) AS [t2]
      ORDER BY [t0].[Key], [t1].[Type], [t2].[Id]

public class PageEvents : PdfPageEventHelper

{

        PdfTemplate _backgroundImageTemplate;



        public override void OnStartPage(PdfWriter writer, Document document)

        {

            base.OnStartPage(writer, document);

            writer.DirectContent.AddTemplate(_backgroundImageTemplate, 0, 0);

        }



        public override void OnOpenDocument(PdfWriter writer, Document document)

        {

            _backgroundImageTemplate = writer.DirectContent.CreateTemplate(document.PageSize.Width, document.PageSize.Height);

        }



        public override void OnCloseDocument(PdfWriter writer, Document document)

        {

            base.OnCloseDocument(writer, document);



            iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(

			@"C:\My Pictures\bg.png");

            img.Alignment = iTextSharp.text.Image.UNDERLYING;

            img.SetAbsolutePosition((document.PageSize.Width - img.Width) / 2, (document.PageSize.Height - img.Height) / 2);

            _backgroundImageTemplate.AddImage(img);

        }

}

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(MyModel model, IEnumerable<HttpPostedFileBase> files)
{
            // code
            return View();
}

[HttpPost]
        public ActionResult Save(MyModel model, IEnumerable<HttpPostedFileBase> files)
        {
            
                var sModel = new MyViewModel
                {
                    MainPhoto = model.MainPhoto,
                    Phone = model.Phone,
                    Title = model.Title,
                    WebSiteUrl = model.WebSiteUrl,
    // ....
                };
                if (files != null)
                {
                    var images = files.Select(file => new Image
                    {
                        FileName = Helpers.Helper.UploadFile(file)
                    }).ToList();
                    sModel.Images = images;
                }
                _locationService.AddLocation(sModel);
                _uow.SaveAllChanges();
            
            return RedirectToAction("List");
        }